Possible reasons for the loss of gear indication on the automatic transmission:
1. Faulty gear selector position sensor:
* Monitors the position of the gear shift lever and transmits information to the transmission ECU.
*A faulty sensor may send erroneous signals, resulting in loss of gear indication.
2. Wiring problems:
* Intermittent or loose electrical connections can disrupt communication between the shift position sensor and the transmission ECU.
*Damaged or loose wires may result in unreliable or missing gear indication.
3. Faulty transmission ECU:
* The transmission ECU processes the signals from the gear selector position sensor and controls the gear indicator.
*A faulty ECU may not interpret signals accurately or may not display gears correctly.
4. Instrument cluster malfunction:
* The instrument cluster is responsible for displaying the gear indication.
*A faulty module or burnt out bulbs may cause the transmission indication to be lost.
5. Low automatic transmission fluid level:
*Low automatic transmission fluid levels can cause problems with the hydraulic system and lead to inaccurate gear indications.
Diagnosis and elimination:
*Check Shift Position Sensor: Check the sensor for visible damage or loose connections.
* Wiring Inspection: Inspect the wiring for damage, breaks or poor connections.
*Transmission ECU Diagnosis: Use a diagnostic scan tool to check for trouble codes and check transmission ECU parameters.
* Checking the instrument cluster: Check the wiring connecting the instrument cluster to the transmission ECU. Make sure all light bulbs are working properly.
*Checking the automatic transmission fluid level: Check the automatic transmission fluid level and add if necessary.
If the above steps fail, further diagnosis and repair may be required by a qualified mechanic.